Fuel cut or detonation?

[BlackMKIII]

While driving with my nice new boost controller, I hear a popping noise from the exhaust and the car bucks a little. I know that fuel cut is normally a BIG hit, then it builds boost again and another BIG hit. But this is different.

What is happening is more "rapid fire," popping accompanied by a less extreme bucking. I'm not running excessively rich or lean, so I'm a little puzzled. No MIL either, like fuel cut always does.

Mods:
Cold air intake, 2.5" IC piping, 3" IC, full 3" exhaust, APEXi AFC Neo, GReddy PRofec B Spec II, stock twins.

 

[lagged]

check your plugs.

 

[tissimo]

check your plugs.

+1 sounds like a missfire

 

[The Reaper]

check plugs.

if the plugs are replaced or fine and it still does it. get in there and check those coilpacks. if they are cracked they will cause that too. Use 1" heat shrink from Ace hardware. that stuff is AWESOME.

if the plugs are fine, and coils are fine...........................................its the dreaded ecu

EDIT: but seeing that you have a new BC, i'm sure your plugs need to be gapped down smaller. sounds like higher pressure is blowing out the spark like a candle.

 

[BlackMKIII]

Hahaha. Wow, thanks guys. I'll check them for sure. If I'm boosting around 17 PSI, what should I have them gapped at?

 

[suprastanger507mgte]

Hahaha. Wow, thanks guys. I'll check them for sure. If I'm boosting around 17 PSI, what should I have them gapped at?

26 - 28 would be a good gapping. Most run around 28. I've run on both plug gaps and never had any issues.

 

[The Reaper]

yea i was running 16 psi on my twins and had them gapped at .26

i was having the same retarded missfire before i tore my 1J down. i used heat shrink on the coils this weekend, and im swapping ecu's so once its running i wont be able to tell what caused it lol

 

[lagged]

actually i ment to check your plugs to get an indication if youve been leaning out.

it could be that they are improperly gapped, fuel cut, or you could be detonating. what you described could be detonation so dont rule that out just yet.

 

[BlackMKIII]

Well, they're coming out in a couple of hours.

 

[lagged]

before you remove them, get the car warmed up and do a WOT blast for a few seconds, maybe in 3rd till redline.

then as soon as possible get the car back and shut it down.

after that, there are lots of online resources to help you read the plugs.

 

[got_boosted]

before you remove them, get the car warmed up and do a WOT blast for a few seconds, maybe in 3rd till redline.

then as soon as possible get the car back and shut it down.

after that, there are lots of online resources to help you read the plugs.

3rd at redline in my car is ~100mph... Let's not suggest anything illegal here shall we? :icon_razz

I had this same issue a few days ago when somehow my EBC got switched over to high boost by accident. Right around 16-17psi I think it started to pop and lose power. It sure seemed like blowout to me, but I'm not tuned and I'm not turning the boost up to find out until I am.

Collin

 

[BlackMKIII]

Well, the plugs look normal, and I'm about to check the gap. My biggest issue is they are Bosch (>.<), and no NGK replacements immediately available. I'm kind of in the middle of working as well. I'll post updates in about 1/2 an hour.

I will say this, though. I'd rather be working on THESE plugs than the ones in my old 7M-GE.

 

[tissimo]

Gap em to .025 and the problem should go away. You might have cracks in your coilbacks as well. Check them out too..

 

[BlackMKIII]

Coilpacks have been heat shrinked already. .025 you say? seems small. *looks at his feeler gauge* Hmmm.....

 

[BlackMKIII]

WOW. .032 spark plug gap. I'm definitely setting them down.

 

[tissimo]

try .028 first then

 

[BlackMKIII]

FAAAAAAAAACCCCCCCKKKKKKKKKKKKKKKKKKKKK!!!!!!!!!!!!!!!!!!!!!!!!

I snapped an electrode!!!!! I'm going to Kragen to pick up a set for a 2JZ-GTE. NGK V-powers. I'll gap them to .028 when I get back.

:madfawk:

 

[BlackMKIII]

Got the new plugs, gapped them to .028, and made a run at high boost. I'll tell you what, it feels SO much better. I'm seriously loving 1.2 Bar now.

 

[tlo86]

Got the new plugs, gapped them to .028, and made a run at high boost. I'll tell you what, it feels SO much better. I'm seriously loving 1.2 Bar now.

sweet so it was just the plugs

 

[BlackMKIII]

I said it's better, not perfect. I need 6097's to make it perfect. :biglaugh: